scholarly journals VISCOSITY OF MONO-, DI- AND TRIETHYLENE GLYCOL AQUEOUS SOLUTIONS AT 298.15 K

2019 ◽  
Vol 62 (6) ◽  
pp. 41-46
Author(s):  
Valentin V. Loskutov
Keyword(s):  
Aqueous Solutions ◽  
Diethylene Glycol ◽  
Complex Structure ◽  
Molar Fraction ◽  
Triethylene Glycol ◽  
Water Mixture ◽  
Viscosity Deviation ◽  
Excess Viscosity ◽  
Wide Range ◽  
Monoethylene Glycol

The aim of this study was to analyze the change in the complex structure formed in water-glycols mixture under mixture composition. The dynamic viscosity for various glycol (mono-, di- and triethylene glycol) aqueous solutions have been measured over wide range of concentration at temperature 25 °C and atmospheric pressure. The new scale of viscosity concentration dependences of various glycols for common description in range of low glycol composition was suggested. From experimental data, the excess viscosity (deviation in viscosity) was calculated. Excess viscosity was negative for monoethylene glycol – water mixture over the entire range of composition. In the case diethylene glycol –water mixture excess viscosity values were found to be negative between 0 and 20 mol %, then became positive in the diethylene glycol rich region. In the case triethylene glycol – water mixture excess viscosity values were negative between 0 and 10 mol %. The Grunberg-Nissan parameter was calculated. By comparing the monoethylene glycol – water hydrogen bonding, reported in literature and Grunberg-Nissan parameter variation versus glycol molar fraction, a correspondence between Grunberg-Nissan parameter and the complex varieties was established. It was shown, that concentration dependence of the Grunberg-Nissan parameter separates the different concentration regions. The variation of the Grunberg-Nissan parameter with glycol molar fraction deals with the interaction variation between water and glycol molecules, the Grunberg-Nissan parameter slop varies.

scholarly journals Thermodynamics of Mg–Al Order-Disorder Reaction in MgAl2O4-Spinel: Constrained by Prolonged Annealing Experiments at 773–1123 K

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 872
Author(s):  
Yunlu Ma ◽  
Xinjian Bao ◽  
Xi Liu
Keyword(s):  
Spinel Structure ◽  
Structural Model ◽  
Molar Fraction ◽  
Thermodynamic Models ◽  
Mgal2o4 Spinel ◽  
Cation Order ◽  
Prolonged Annealing ◽  
Wide Range ◽  
History Of ◽  
Annealing Experiments

MgAl2O4-spinel has wide industrial and geological applications due to its special structural and physical–chemical features. It is presumably the most important endmember of complex natural spinel solid solutions, and therefore provides a structural model for a large group of minerals with the spinel structure. There exists a well known but still inadequately understood phenomenon in the structure of MgAl2O4-spinel, the Mg–Al cations readily exchanging their positions in response to variations of temperature, pressure, and composition. A large number of experiments were performed to investigate the Mg–Al cation order-disorder process usually quantified by the inversion parameter x (representing either the molar fraction of Al on the tetrahedral T-sites or the molar fraction of Mg on the octahedral M-sites in the spinel structure), and some thermodynamic models were thereby constructed to describe the x-T relation. However, experimental data at some key T were absent, so that the different performance of these thermodynamic models could not be carefully evaluated. This limited the interpolation and extrapolation of the thermodynamic models. By performing some prolonged annealing experiments with some almost pure natural MgAl2O4-spinel plates and quantifying the x values with single-crystal X-ray diffraction technique, we obtained some critical equilibrium x values at T down to 773 K. These new x-T data, along with those relatively reliable x values at relatively high T from early studies, clearly indicate that the CS94 Model (a model constructed by Carpenter and Salje in 1994) better describes the Mg–Al cation order-disorder reaction in MgAl2O4-spinel for a wide range of T. On the basis of the CS94 Model, a geothermometer was established, and its form is T-closure = 21362 × x3 − 12143 × x2 + 6401 × x − 10 (T-closure standing for the closure temperature of the Mg–Al cation exchange reaction). This geothermometer can be used to constrain the thermal history of the geological bodies containing MgAl2O4-spinel.

Experimental and Numerical Study of Methanol-Water Mixture Single-Phase Heat Transfer in a Micro-Channel Heat Sink

2012 ◽  
Author(s):  
Chun K. Kwok ◽  
Matthew M. Asada ◽  
Jonathan R. Mita ◽  
Weilin Qu
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Sink ◽  
Single Phase ◽  
Numerical Study ◽  
Pure Water ◽  
Molar Fraction ◽  
Water Mixture ◽  
Micro Channel ◽  
Numerical Predictions

This paper presents an experimental study of single-phase heat transfer characteristics of binary methanol-water mixtures in a micro-channel heat sink containing an array of 22 microchannels with 240μm × 630μm cross-section. Pure water, pure methanol, and five methanol-water mixtures with methanol molar fraction of 16%, 36%, 50%, 63% and 82% were tested. Key parametric trends were identified and discussed. The experimental study was complemented by a three-dimensional numerical simulation. Numerical predictions and experimental data are in good agreement with a mean absolute error (MAE) of 0.87%.

scholarly journals Oil in Water Monitoring Using Advanced Light Scattering

2013 ◽  
Author(s):  
Gernot Seebacher ◽  
Axel A. Schmidt ◽  
Jochen Offermann
Keyword(s):  
Light Scattering ◽  
Oil Content ◽  
Scattered Light ◽  
Discharge Process ◽  
Water Mixture ◽  
Effluent Quality ◽  
Light Pattern ◽  
Bilge Water ◽  
Oil In Water ◽  
Wide Range

The paper provides background on how bilge water has changed over the years and how technology has enabled manufacturers to stay ahead of the curve by borrowing technological breakthroughs from other areas to the measurement of oil content in the marine environment. Light scattering provides today a universal and reliable method, able to measure the wide range of oils present in a wildly variable and unpredictable bilge water mixture. Bilge water regulations were put in place to reduce the potential of harm to the environment from oily bilge water discharges. Regulations require that instruments verify effluent quality continually during the discharge process, which precludes the adoption for shipboard use of standard laboratory style testing with the associated time delays to complete the analysis. Measuring oil content with the light scattering measuring instrument is a tried and tested means for compliant bilge water verification. State of the art instruments employ sophisticated light measuring systems and they use complex algorithms to convert the scattered light pattern values into oil content reading, thereby considering interference from other than oil suspended matter, they prevent harm to the environment from bilge water discharges. Paper published with permission.

Modeling of the Extraction of Lanthanide Nitrates from Aqueous Solutions Over a Wide Range of Activities by CMPO

2004 ◽  
Vol 22 (5) ◽  
pp. 791-811 ◽  
Author(s):  
S. Belair ◽  
C. Lamouroux ◽  
M. Tabarant ◽  
A. Labet ◽  
C. Mariet ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Wide Range ◽  
Lanthanide Nitrates

scholarly journals COMPARATIVE ANALYSIS OF DIFFERENT CRITERIA OF SITE STRUCTURAL STABILITY IN THE TIME SERIES

2019 ◽  
pp. 119-128
Author(s):  
Liliya Andreevna Landman ◽  
Andrei Vladimirovich Faddeenkov
Keyword(s):  
Time Series ◽  
Regression Model ◽  
Structural Changes ◽  
Least Squares Method ◽  
Complex Structure ◽  
Standard Normal Distribution ◽  
Regression Equations ◽  
Unknown Parameters ◽  
Chow Test ◽  
Wide Range

The concept of structure is used to describe a set of stable relations between the main parts of the object, which describe its integrity and identity, i.e, preserving the basic properties for a wide range of internal and external changes. This concept usually relates to the concepts of system and organization. The structure expresses a stable part of the system that is slightly changed during different reforms. Over the years structural changes take place because of active economic policy or as a result of spontaneous, uncontrollable processes. Therefore, it seems to be quite natural to find out whether there have been structural changes in the observation period, and to find them reflected in the specification of the model. The basic ideas of methods for determining structural changes in the time series dynamics have been considered, such as Chow test, Gujarati test and Poirier method. The power study was conducted for the three possible cases of change in time series trends. The random error was modeled according to the standard normal distribution. A linear multiple regression model with three independent variables was used as a time series model. Estimation of the vector of unknown parameters of the model was conducted using least squares method. For each of the three criteria the of test the null hypothesis about time series instability was carried out using the F -criterion, which involves finding the residual sum of squares of a regression model and analysis of correlation between its decline and the loss of degrees of freedom. It can be noted that Gujarati and Poirier equations have a more complex structure than equation of Chow test; however, using Chow test assumes estimation of the parameters of the three regression equations.

Drag Coefficient and Two-Phase Friction Multiplier on Tube Bundles Subjected to Two-Phase Cross-Flow

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
W. G. Sim ◽  
Njuki W. Mureithi
Keyword(s):  
Drag Coefficient ◽  
Void Fraction ◽  
Euler Number ◽  
Tube Bundle ◽  
Cross Flow ◽  
Water Mixture ◽  
Duct Flow ◽  
Two Phase ◽  
Mass Fluxes ◽  
Wide Range

An approximate analytical model, to predict the drag coefficient on a cylinder and the two-phase Euler number for upward two-phase cross-flow through horizontal bundles, has been developed. To verify the model, two sets of experiments were performed with an air–water mixture for a range of pitch mass fluxes and void fractions. The experiments were undertaken using a rotated triangular (RT) array of cylinders having a pitch-to-diameter ratio of 1.5 and cylinder diameter 38 mm. The void fraction model proposed by Feenstra et al. was used to estimate the void fraction of the flow within the tube bundle. An important variable for drag coefficient estimation is the two-phase friction multiplier. A new drag coefficient model has been developed, based on the single-phase flow Euler number formulation proposed by Zukauskas et al. and the two-phase friction multiplier in duct flow formulated by various researchers. The present model is developed considering the Euler number formulation by Zukauskas et al. as well as existing two-phase friction multiplier models. It is found that Marchaterre's model for two-phase friction multiplier is applicable to air–water mixtures. The analytical results agree reasonably well with experimental drag coefficients and Euler numbers in air–water mixtures for a sufficiently wide range of pitch mass fluxes and qualities. This model will allow researchers to provide analytical estimates of the drag coefficient, which is related to two-phase damping.

THE ACTIVATION OF PURIFIED HUMAN PLASMINOGEN IN SOLUTIONS OF ETHYLENE GLYCOLS

1963 ◽  
Vol 41 (1) ◽  
pp. 889-895 ◽  
Author(s):  
Phyllis S. Roberts
Keyword(s):  
Methyl Ester ◽  
Ethylene Glycol ◽  
Diethylene Glycol ◽  
Room Temperature ◽  
Fast Rate ◽  
Triethylene Glycol ◽  
Ethylene Glycols ◽  
Human Plasminogen ◽  
Glycol Solution ◽  
Rate Of Accumulation

Ethylene glycols have been found to allow activation of purified preparations of human plasminogen. The activity of the enzyme formed, plasmin, was measured using TAMe (p-toluene-sulphonyl-L-arginine methyl ester) as a substrate. In 50% (v/v) solutions of these compounds at pH 7.6 and 30 °C, plasmin accumulated faster in diethylene and triethylene glycols than in glycerol, but in ethylene glycol no plasmin was found. When lower concentrations of ethylene glycol (from zero to 50%) and shorter times of incubation were used, plasmin was found. With equimolar solutions (4.3 M) of glycerol and the three glycols, only diethylene glycol showed a fast rate of accumulation of plasmin. A 50% triethylene glycol solution partially inhibited the rate of spontaneous activation but stabilized the plasmin formed and therefore enzyme accumulated. At room temperature more plasmin accumulated than at higher temperatures when plasminogen was incubated in 50% triethylene glycol solution, and no plasmin was found when plasminogen was incubated at pH 7.6, 30 °C, in 50% solutions of propylene glycols, several ethers of the ethylene glycols, several polymers of various glycols, and dioxane.

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